// Copyright 2021-2022 EMQ Technologies Co., Ltd.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package operator

import (
	"fmt"

	"github.com/lf-edge/ekuiper/internal/xsql"
	"github.com/lf-edge/ekuiper/pkg/api"
	"github.com/lf-edge/ekuiper/pkg/ast"
)

type OrderOp struct {
	SortFields ast.SortFields
}

/**
 *  input: *xsql.Tuple from preprocessor | xsql.WindowTuples from windowOp | xsql.JoinTuples from joinOp
 *  output: *xsql.Tuple | xsql.WindowTuples | xsql.JoinTuples
 */
func (p *OrderOp) Apply(ctx api.StreamContext, data interface{}, fv *xsql.FunctionValuer, afv *xsql.AggregateFunctionValuer) interface{} {
	log := ctx.GetLogger()
	log.Debugf("order plan receive %v", data)
	sorter := xsql.OrderedBy(p.SortFields, fv, afv)
	switch input := data.(type) {
	case error:
		return input
	case xsql.TupleRow:
		return input
	case xsql.SortingData:
		if err := sorter.Sort(input); err != nil {
			return fmt.Errorf("run Order By error: %s", err)
		}
		return input
	default:
		return fmt.Errorf("run Order By error: expect xsql.Valuer or its array type")
	}
}